243 questions

[cornhusker]

I know this caliber is noted for a barrel burner,but what the heck. I am playing with the idea of building a 243 for f class with a max. distance of 500 yards.
My question is what would be the best twist to go with. And I am also thinking bull barrel..And to what length might be best to get. And the final question
is should I have it throated a little longer ...? I had a few guys say the standard length chamber should be ok...Thanks for any advice or ideas..

 

[sierracharlie338]

I happen to have a GAP built 243 for sale just FYI (only has 49 rounds through it and comes with a bunch of amaxs).

To answer your questions:

8 twist will be perfect for 105 AMAXs and no need to throat it longer (per the guys at GAP) for the amax. I went with a rem Varmint profile but you wouldn't be worse off with a bull either. I would suggest 24-26 inches IMHO.

Hope this helps.

 

[FatBoy]

For a dedictaed F Class rifle, regardless of distance, use the heaviest, longest barrel you can make weight with. A 30" 1.25 cylinder is normal. I would go with a between a 7 - 8 twist, with the bullet you plan on using in mind. If you want to shoot the new Sierra 110s or the Tubb 115s, a 7 twist (maybe faster) is recommended. For 105/107, I agree 8 is plenty.

For the distance you've listed, 243win is probably a bit much but you leave yourself open to move to 1k with zero modifications.

 

[Rob01]

For the chamber you should pick the bullet you plan on using and let your smith know. He can chamber the rifle accordingly.

Barrel contour, "bull" is a generic term for a heavy barrel. I know some companies have actually started making it as a contour but speaking in actual contours would be best. For your use an MTU, Heavy Varmint or M24/40 would all be good contours. If you have a weight limit in your class that should come into the decision as well.

Length? I would go around 28". This way you can get velocity easier.

Twist? Again depends on bullet used. If going with the heavier 110-115 then go with a 7-7.5 twist. If 105s then the 7.5-8 would work. Mine has an 8.5 twist and it shoots the 105s great. A good all around would be a 7.5.